The current study evaluated processes underlying two common symptoms (i.e., state regulation problems and deficits in auditory processing) associated with a diagnosis of autism spectrum disorders. Although these symptoms have been treated in the literature as unrelated, when informed by the Polyvagal Theory, these symptoms may be viewed as the predictable consequences of depressed neural regulation of an integrated social engagement system, in which there is down regulation of neural influences to the heart (i.e., via the vagus) and to the middle ear muscles (i.e., via the facial and trigeminal cranial nerves). Respiratory sinus arrhythmia (RSA) and heart period were monitored to evaluate state regulation during a baseline and two auditory processing tasks (i.e., the SCAN tests for Filtered Words and Competing Words), which were used to evaluate auditory processing performance. Children with a diagnosis of autism spectrum disorders (ASD) were contrasted with aged matched typically developing children. The current study identified three features that distinguished the ASD group from a group of typical developing children: 1) baseline RSA, 2) direction of RSA reactivity, and 3) auditory processing performance. In the ASD group, the pattern of change in RSA during the attention demanding SCAN tests moderated the relation between performance on the Competing Words test and IQ. In addition, in a subset of ASD participants, auditory processing performance improved and RSA increased following an intervention designed to improve auditory processing.

The use of heart rate measures in research requires accurate detection and timing of beat-to-beat values. Numerous technologies are available to researchers; however, benchmarking of a specific apparatus is seldom conducted. Since heart rate variability provides a portal to the neural regulation of the heart, accurate detection and timing of beat-to-beat values is essential to both basic physiological research and the clinical application of heart rate variability measures. The current study evaluated the accuracy of an ambulatory system, the LifeShirt® (Vivometrics), relative to a standard laboratory-based heart rate monitoring equipment (Biopac), during baseline and exercise conditions. LifeShirt® performed equivalently to the Biopac during both conditions, experienced few errors of detection, generated similar times between sequential heart periods, and produced similar summary indices of heart rate and heart rate variability.Keywords ambulatory monitoring; heart period; respiratory sinus arrhythmia; baseline; exercise Accurate detection and timing of beat-to-beat heart rate is necessary in medical, psychophysiological, and physiological research. To obtain accurate measurements with msec accuracy, researchers have been limited to laboratory-based equipment. An ability to obtain accurate beat-to-beat measures of heart rate in an ambulatory device would provide important opportunities to evaluate the dynamic regulation of the heart in contexts consistent with naturally occurring demands. Vivometrics recently introduced a noninvasive physiological monitoring system (LifeShirt®) with capabilities to monitor multiple physiological parameters including R-R intervals and several respiratory parameters. While several researchers have used the LifeShirt® system in various studies (Grossman, 2004;Keenan, 2004;Keenan & Wilhelm, 2005a;Keenan & Wilhelm, 2005b;Wilhelm et al., 2003) or acknowledged the potential applicability of the LifeShirt® in future studies (Bruton & Thomas, 2006;Stefanov et al., 2004), the accuracy and precision of the LifeShirt® in the detection of beat-to-beat heart rate has yet to be tested against a standard laboratory-based heart rate monitoring equipment. Thus, the purpose of the study is to compare the accuracy and precision of heart rate detections by the ambulatory LifeShirt® with the values generated by a laboratory-based physiological monitoring system. The Biopac MP35 (Bipoac Systems, Goleta, CA, USA) was chosen as the Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. standard for comparison, since it is frequently used as both a teaching and ...

Respiratory sinus arrhythmia (RSA), heart period, and motor activity were monitored in preschoolers during a variety of tasks varying in required movement. The data analyses indicate: (1) that when activity increases during tasks, there are synchronous decreases in heart period and RSA; (2) that correlations between changes in RSA and heart period are related to activity only during exercise when there is a major demand for increased metabolic resources; and (3) that the covariation among the variables within each condition is low except during exercise. These findings suggest that the slight increases in motor activity (i.e., hand movements) often required in attention demanding psychophysiological protocols are not related to RSA and heart period responses. However, when tasks necessitate large increases in motor activity (e.g., exercise), the decreases in heart period and RSA are related to the change in motor activity.

The evolution of the autonomic nervous system provides an organizing principle to interpret the adaptive significance of physiological systems in promoting social behavior and responding to social challenges. This phylogenetic shift in neural regulation of the autonomic nervous system in mammals has produced a neuroanatomically integrated social engagement system, including neural mechanisms that regulate both cardiac vagal tone and muscles involved in vocalization. Mammalian vocalizations are part of a conspecific social communication system, with several mammalian species modulating acoustic features of vocalizations to signal affective state. Prosody, defined by variations in rhythm and pitch, is a feature of mammalian vocalizations that communicate emotion and affective state. While the covariation between physiological state and the acoustic frequencies of vocalizations is neurophysiologically based, few studies have investigated the covariation between vocal prosody and autonomic state. In response to this paucity of scientific evidence, the current study explored the utility of vocal prosody as a sensitive index of autonomic activity in human infants during the Still Face challenge. Overall, significant correlations were observed between several acoustic features of the infant vocalizations and autonomic state, demonstrating an association between shorter heart period and reductions in heart period and respiratory sinus arrhythmia following the challenge with the dampening of the modulation of acoustic features (fundamental frequency, variance, 50% bandwidth, and duration) that are perceived as prosody.

Autonomic reactivity was studied in individuals with fragile X syndrome (FXS), a genetic disorder partially characterized by abnormal social behavior. Relative to age-matched controls, the FXS group had faster baseline heart rate and lower amplitude respiratory sinus arrhythmia (RSA). In contrast to the typically developing controls, there was a decrease in RSA with age within the FXS group. Moreover, within the FXS group heart rate did not slow with age. The FXS group also responded with an atypical increase in RSA to the social challenge, while the control group reduced RSA. In a subset of the FXS group, the autonomic profile did not change following 2 months and 1 year of lithium treatment. The observed indices of atypical autonomic regulation, consistent with the Polyvagal Theory, may contribute to the deficits in social behavior and social communication observed in FXS.